package com.zoke.videolist.util;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.provider.MediaStore;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;


import com.zoke.videolist.R;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Collections;
import java.util.Map;
import java.util.Stack;
import java.util.WeakHashMap;

public class VideoThumbLoader {

    private Context context;

    private Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
    private Map<String, Bitmap> videoBitmap = Collections.synchronizedMap(new WeakHashMap<String, Bitmap>());


    public VideoThumbLoader(Context context) {
        //Make the background thead low priority. This way it will not affect the UI performance
        this.context = context;
        photoLoaderThread.setPriority(Thread.NORM_PRIORITY - 1);
    }


    final int stub_id = R.drawable.nophotos;

    public void DisplayImage(String url, ImageView imageView, ProgressBar progressBar) {
        imageViews.put(imageView, url);
        Bitmap bitmap = videoBitmap.get(url);

        if (bitmap != null) {
            imageView.setImageBitmap(bitmap);
            if (progressBar != null)
                progressBar.setVisibility(View.INVISIBLE);
        } else {
            queuePhoto(url, imageView, progressBar);
            imageView.setImageResource(stub_id);
        }
    }

    private void queuePhoto(String url, ImageView imageView, ProgressBar progressBar) {
        //This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. 
        photosQueue.Clean(imageView);
        PhotoToLoad p = new PhotoToLoad(url, imageView, progressBar);
        synchronized (photosQueue.photosToLoad) {
            photosQueue.photosToLoad.push(p);
            photosQueue.photosToLoad.notifyAll();
        }

        //start thread if it's not started yet
        if (photoLoaderThread.getState() == Thread.State.NEW)
            photoLoaderThread.start();
    }

    private Bitmap getBitmap(String url) {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inSampleSize = 1;
        Bitmap curThumb = MediaStore.Video.Thumbnails.getThumbnail(
                context.getContentResolver(),
                Long.parseLong(url), MediaStore.Video.Thumbnails.MINI_KIND, options);
        return curThumb;
    }

    //decodes image and scales it to reduce memory consumption
    private Bitmap decodeFile(File f) {
        try {
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(f), null, o);

            //Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE = 80;
            int width_tmp = o.outWidth, height_tmp = o.outHeight;
            int scale = 1;
            while (true) {
                if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE)
                    break;
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }

            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
        } catch (FileNotFoundException e) {
        }
        return null;
    }

    //Task for the queue
    private class PhotoToLoad {
        public String url;
        public ImageView imageView;
        public ProgressBar progressBar;

        public PhotoToLoad(String u, ImageView i, ProgressBar p) {
            url = u;
            imageView = i;
            progressBar = p;
        }
    }

    PhotosQueue photosQueue = new PhotosQueue();

    public void stopThread() {
        photoLoaderThread.interrupt();
    }

    //stores list of photos to download
    class PhotosQueue {
        private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>();

        //removes all instances of this ImageView
        public void Clean(ImageView image) {
            for (int j = 0; j < photosToLoad.size(); ) {
                if (photosToLoad.get(j).imageView == image)
                    photosToLoad.remove(j);
                else
                    ++j;
            }
        }
    }

    private class PhotosLoader extends Thread {
        public void run() {
            try {
                while (true) {
                    //thread waits until there are any images to load in the queue
                    if (photosQueue.photosToLoad.size() == 0)
                        synchronized (photosQueue.photosToLoad) {
                            photosQueue.photosToLoad.wait();
                        }
                    if (photosQueue.photosToLoad.size() != 0) {
                        PhotoToLoad photoToLoad;
                        synchronized (photosQueue.photosToLoad) {
                            photoToLoad = photosQueue.photosToLoad.pop();
                        }
                        Bitmap bmp = getBitmap(photoToLoad.url);
                        videoBitmap.put(photoToLoad.url, bmp);
                        String tag = imageViews.get(photoToLoad.imageView);
                        if (tag != null && tag.equals(photoToLoad.url)) {
                            BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad.imageView, photoToLoad.progressBar);
                            Activity a = (Activity) photoToLoad.imageView.getContext();
                            a.runOnUiThread(bd);
                        }
                    }
                    if (Thread.interrupted())
                        break;
                }
            } catch (InterruptedException e) {
                //allow thread to exit
            }
        }
    }

    private PhotosLoader photoLoaderThread = new PhotosLoader();

    //Used to display bitmap in the UI thread
    class BitmapDisplayer implements Runnable {
        Bitmap bitmap;
        ImageView imageView;
        ProgressBar progressBar;

        public BitmapDisplayer(Bitmap b, ImageView i, ProgressBar p) {
            bitmap = b;
            imageView = i;
            progressBar = p;
        }

        public void run() {
            if (bitmap != null)
                imageView.setImageBitmap(bitmap);
            else
                imageView.setImageResource(stub_id);
            if (progressBar != null) progressBar.setVisibility(View.INVISIBLE);

        }
    }
}
